© 2018 Scoliosis Research Society Study Design: The question was addressed in three ways: (1) a query of Kids' Inpatient Database (KID) to obtain nationally representative data; (2) retrospective review of cases at a single institution; (3) survey of Scoliosis Research Society (SRS) spine surgeons. Objectives: Evaluate the rate of immediate postoperative pulmonary complications, risk factors, and relevant surgeon practice patterns, to determine the usefulness of routine postoperative chest radiographs after posterior spinal instrumentation and fusion (PSIF) for adolescent idiopathic scoliosis (AIS). Summary of Background Data: Routine postoperative chest radiography after PSIF for AIS is performed in many institutions to evaluate for acute pulmonary complications, particularly pneumothorax (PTX). The incidence of pneumothorax and its effect on management is unknown. Methods: The frequency of PTX and surgical intervention were recorded. We evaluated associations between PTX and patient demographics or comorbidities, as well as survey respondent demographics and their practice patterns. Results: In the KID data sets, the risk of PTX after PSIF for AIS patients was 0.3% (30/9,036), with intervention required in 13.3% (4/30) of PTX-positive patients (0.04% of all cases). Review of cases at our institution revealed a PTX rate of 3.3% (8/244) by radiology report. No surgical intervention was required. Patients with PTX had, on average, an increased number of vertebrae fused (p = .012), a proximal thoracic scoliosis curve location (p = .009), and/or an intraoperative blood transfusion (p = .002). SRS respondents reported a PTX risk of 0.8% (87/11,318), and 32.2% (89/276) of respondents indicated routine use of postoperative chest radiographs. Of those, 46.1% (41/89) specified willingness to change practice patterns if provided evidence of low PTX rates. Conclusions: Pneumothorax is uncommon after PSIF for AIS. The need for intervention is even less common. Routine postoperative chest radiographs are of questionable value after PSIF for AIS. Level of Evidence: Level III.